Soil Resources of European Volcanic Systems



Faial island, Azores - april 1999

Date of description: 29-04-1999

Authors: A.G. Jongmans, and F. van   Oort 

Location: Faial island, Azores

Altitude: 510 m


Map number and Coordinates: 

WRB (2001): Hyperdystri-Silandic Andosol
ST (1999): Medial, amorphic, mesic Typic Hapludand

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Soil Climate: Mesic temperature regime, Udic moisture regime.

Topography: Gently undulating

Landform: Volcano

Land element: Slope

Position: Middle slope

Slope: Steep, 10-15%

Form: Concave

Landuse/Vegetation: Extensive grazing, pasture

Human influences: Profile is situated in a road cut, renewed for 1 m.

Parent material: Pyroclastic material.

Effective soil depth: Deep

Erosion: No erosion features visible.

Drainage class: Well drained

Moisture conditions: Slightly moist



Ah: 0-10 cm; dark brown (7.5YR 3/2); silt loam; few fine to medium gravel consisting of white pumice- and dark basaltic fragments, partially weathered; weak, very fine (sub) angular blocky structure; friable; few very fine to fine pores; common fine roots; 0-5 cm Fe coatings round pores; abrupt and smooth to:

A/C: 10-30 cm; brown to dark brown (10YR 4/3) brown (10YR 5/3); disturbed layered loamy sand; common fine to medium slightly to strongly weathered gravel consisting of pumice; friable and firm; few fine pores; few fine roots; abrupt and smooth to:

2Ahb: 30-45 cm; dark brown (7.5YR 3/2); clay loam; very few, very fine gravel; moderate, medium, compound rough prismatic structure, subdivided into weak, very fine, (sub)angular blocky structure; friable; common very fine and fine pores; few very fine roots; slightly thixotropic; gradual and smooth to;

2Bwb: 45-65 cm; brown to dark brown (7.5YR 4/3); clay loam; weak very fine and fine subangular and angular blocky structure; friable; many very fine and fine pores; few very fine and fine roots; in the lower part of the horizon occurrence of angular fragments of the 2 C1 horizon; gradual and smooth to:

2Bwb/2C: 65-90 cm; This horizon consists of two parts: 2Bw material already described and angular pieces of 2C1 material which are described below; in the 2Bw material presence of fine textured allophane coatings with Fe compounds, diameter 1 mm.; clear and smooth to:

2C: 90-110 cm; very dark grey (10YR 3/1); clay loam; structureless massive; firm to extremely hard; presence of skew planes, coated by fine textured material dark yellowish brown (10YR 4/6) to yellowish brown (10YR 5/8), and Fe coatings, dark reddish brown (5YR 3/4), few very fine pores coated with fine textured material 2.5YR 8/4(?) and Mn coatings black (10YR 2/1); abrupt and wavy to:

3C: 110-130 cm; indurated lapilli, partially covered by iron, very dark greyish brown (10YR 3/2), partially altered and thixotropic, locally allophane coatings 2.5YR 8/4(?); clear and smooth to:

4BC: 130-145 cm; brown to dark brown (7.5YR 4/4); clay loam; weak very fine to fine subangular blocky structure; friable; many fine pores; 40% totally altered pumice fragments, reddish yellow (5YR 6/8); abrupt and smooth to 5Bw (not described)



WRB (2001): ochric horizon (0-10 cm); andic horizon (0-145 cm); Sio > 0.6% between 30 and 100 cm; BS < 20% throughout:

Hyperdystri-Silandic Andosol 

ST (1999): ochric epipedon (0-25 cm); andic soil properties (0-145 cm); mean Sio 1.16%, mean Feo 1.23% between 0 and 100 cm, 8x Sio + 2x Feo > 5, 8x Sio > 2x Feo (Santiago figures): 

Medial, amorphic, mesic Typic Hapludand

Last modified 30 April 2004 by EG